Track-type machines, such as track loaders, are frequently used in applications where the machine must be moved from one job site to another along or across paved roads. One such application is the use of track loaders for preparing building sites and earthworking applications for new homes in residential or buildings in commercial locations and the like. Such work can require a great deal of machine mobilization from one job site to another. Once the streets or parking lots have been completed, machine mobilization becomes a significant problem for track machines equipped only with steel track shoes, as they can then no longer be driven on such paved surfaces without causing significant damage to such surfaces. As a consequence, bridging material must be laid across the street or the track loader must be trucked on a trailer to its next job site. Either of these alternatives are quite time consuming and costly.
Others have attempted to solve this lack of mobility problem by attaching rubber pads to the track shoes by some type of fasteners or clamping devices. Some of such prior art devices are exemplified by the following patents: British Patent No. 1,016,757 issued Jan. 12, 1966; German Patent No. 1,152,631 issued Aug. 8, 1963; U.S. Pat. No. 1,314,722 issued Sep. 2, 1919; U.S. Pat. No. 3,058,783 issued Oct. 16, 1962; and U.S. Pat. No. 4,448,459 issued May 15, 1984 to the Assignee hereof. Heretofore, however, such prior art devices suffered from extremely short lives due to premature failures due to stresses on the rubber, causing the chucking out of large pieces of the rubber from the pads, or due to bond failure between the rubber and the member to which it was bonded.
The present invention is directed to overcoming the shortcomings of the prior attempts by providing a rubber grouser portion that is molded directly to and between a pair of steel grouser bars on a steel track shoe. Direct molding of the rubber grouser to the track shoe is advantageous because it eliminates the expense of separate attaching hardware and requires no modification of the track shoe to receive such hardware. A further advantage of the present invention is that when the rubber grouser portion wears down, so as to no longer be useful for roading, the rubber can be removed. Once this is accomplished, the remaining steel track shoe is essentially new and can be used in any application where roading across paved streets is not required.